Wireless (cellular) networks such as those implementing, for example, General Packet Radio Service (GPRS), Code Division Multiple Access (CDMA)-One, CDMA-2000 and W-CDMA support multimedia messaging service (MMS) in addition to voice and text messaging. Multimedia messaging can take the form of person-to-person (P2P) messaging and application-to-person (or person-to-application) (A2P) messaging. In P2P messaging, messages are sent from one user agent (UA) on a wireless network user's terminal (e.g. a MMS smart phone) to another UA on a second user's terminal and vice versa via a multimedia messaging service center (MMSC). A2P messaging involves messages being sent, via a MMSC, between a UA on a wireless network user's terminal and an application on an application server.
FIG. 1 represents a MMS reference model according to the 3rd Generation Partnership Project TS 23.140 technical specification. The technical specification provides for a protocol, known as MM1, between a user agent (e.g. MMS User Agent A and MMS User Agent B) and a MMSC (e.g. MMS Relay/Server). Another protocol, known as MM4, is provided between pairs of MMSC such as between MMS Relay/Server and “Foreign” MMS Relay/Server.
FIG. 2 represents a schematic diagram of the relationship between a UA 110 and a MMSC 120 in the context of additional entities, a WAP Gateway 130, a WAP Push Proxy 150, a Short Message Service Center (SMSC) 140 and an Application Server 160, that are commonly part of a conventional GPRS or a third generation (3G) wireless network.
A link between the UA 110 and the WAP Gateway 130 supports Wireless Applications Protocol (WAP). A link between the WAP Gateway 130 and the MMSC 120 supports the MM1 protocol. A link between the UA 110 and the SMSC 140 supports the Signal System No. 7 (SS7) protocol. The WAP Push Proxy 150 has a link to the MMSC 120 that supports the Push Proxy Protocol (PAP) (WAP Forun, WAP-247-PAP-20010429-a, “Push Access Protocol”) and a link to the SMSC 140 that supports the Short Message Peer to Peer (SMPP) protocol or other similar protocol such as, for example, Computer Interface to Message Distribution (CIMD), Universal Computer Protocol/External Machine Interface (UCP/EMI) and China Mobile Peer to Peer (CMPP). For the purposes of exchanging MMS messages between the UA 110 and the MMSC 120, the presence to the WAP Push Proxy 150 is effectively transparent.
Note that some of the above named protocols are hierarchical and therefore messages according one protocol can be encapsulated and transported within messages according to another protocol.
FIG. 3 represents a message sequence chart for a number of exemplary MM1 message sequences showing the flow of messages between the UA 100 (MMS UA), the SMSC 140, the WAP Gateway (WAP G/W) 130 and the MMSC 120 as represented in FIG. 2. Note that all unsolicited messages originating from the UA 110 are sent to the WAP Gateway 130 where they are forwarded onto the MMSC 120. Messages originating from the MMSC 120 in response to a message from the UA 110 are sent to the WAP Gateway 130 where they are forwarded onto the UA 110. Unsolicited messages originating from the MMSC 120 are sent to SMSC 140 where they are forwarded onto the UA 110.
Wireless networks can have multiple MMSC 120 for various reasons including, for example, multiple service offerings or service types (e.g. P2P, A2P and MMStore), enhanced performance (e.g. load-balancing), use of multiple MMSC vendors' equipment, server redundancy, geographic dispersion and other similar reasons. Most UA are typically configured with an address, in the form of a universal resource locator (URL), of one MMSC 120. This address is used whenever the UA 110 initiates communication with (i.e. sends a message to) the MMSC 120. In the presence of multiple MMSC there is a problem addressing each individual MMSC 120. The provisioning of a single MMSC 120 address in the UA 110 creates difficulties in exploiting the benefits or multiple MMSC 120 in the network since the multiple MMSC 120 can not be directly addressed by the UA 110. In addition, when an MMSC 120 initiates communication with the UA 110, the messages are typically sent via SMSC 140 and the messages do not always contain the address of the MMSC 120. When responding to messages initiated by the MMSC 120, the UA 110 will always uses the MMSC 120 address with which it is configured. What is needed is a mechanism that provides for a UA to access a range of services provided by a plurality of MMSC 120 while using only a single MMSC 120 address.